Facit Aktiebolag

Telefonaktiebolaget Lm Ericsson (publ)

Sven G Stenudd

Birger H Ek

Lars-Gunnar M Stenudd

The invention relates to a method in printheads (1) with a plurality of print elements (4) arranged movable in relation to each other and a moving mechanism (7, 9, 11, 12, 14) with magnetic field-responsive forces for moving selectable print elements to print or inactive positions. With utilization of the method the forces with which selected print elements are moved in appropriate cases to their print positions can be changed in coordination for a plurality of print elements. In accordance with the invention this is achieved by a magnetic field change coordinated for several print elements. The invention also relates to a printhead (1) with a plurality of first electromagnet means (9, L1 L24) for moving selectable print elements (4) and also a second electromagnet means (LB) common to a plurality of print elements, for coordinated change of the forces for a plurality of print elements with which the print elements can be moved to their print positions. A method and a printhead in accordance with the invention are primarily intended for matrix printers.

Method of moving print elements in printheads and a printhead with

Stepping motor including a runner (2) and at least one stator (4) relative to which the runner is movably mounted. The stator has at least two mutually parallel magnetizing elements (6,8,10) each with a groove-like space (19) extending in the travelling direction of the runner, pole tooth rows (12) being formed on the inside of the defining side walls of said space. The runner (2) carries an armature element (18) in each groove-like space with tooth rows (20) arranged along the pole tooth rows (12) of the magnetizing element such as to close magnetic flux paths in coaction with the armature element tooth rows, said paths extending via said side walls transverse the travelling direction of the runner (2). The parallel armature elements (18) are carried by a common carrying body (16) of non-magnetic material.

Linear stepping motor

A drive means comprising a movable part and a fixed part provided with a stator winding and a magnet yoke with a magnetic gap. A soft-iron magnetic portion is arranged in the magnetic gap. A current generator generates a first current for a stator winding and a second current for another stator winding, the sum of the magnitudes of the two currents being constant. The reluctance effect causes each of two soft-iron magnetic portions to be pulled into an individual magnetic gap driven by one of the two currents. The two reluctance forces vary quadraticly with the two currents, but due to the fact that the net force is the difference between them, this net force will be linearly dependent on the currents. It is suitable to allow the two currents to come from the same amplifier stage, which is push-pull coupled.

Mechanical drive apparatus for providing linear motion in response to

A stepping motor having at least one stator with circularly disposed and equally interspaced poles. A rotor is provided which coacts with the stator and is rigidly connected to a rotatable shaft. The rotor has a number of teeth which corresponds to the number of stator poles, however the pole faces of the rotor teeth are of a different form and size than the pole faces of the stator poles whereby the torque generating intersecting line between the pole faces of the stator poles and the rotor teeth is lengthened when the rotor moves in over a stator pole and shortened when the rotor teeth leaves the stator pole.

Stepping motor

Printing head for a dot matrix printer

A device for marking an information carrying medium has an arm with a pointed tip adapted to engage the medium. The arm is spring biased for movement in one direction, and a solenoid structure is provided for moving the arm in the other direction. A land surface cooperates with the arm to form an air pressure damping arrangement to damp movements of the arm in a direction away from the information carrying medium.

Device for pointwise action on an information carrying medium

A device for producing imprints on a recording medium having a member acting on the medium which strikes or presss against a surface of the medium in its forward position. The member is in the form of an elongated arm being resiliently connected to a frame or other support. The arm is also provided with means to prevent ink from adhering to the member as a result of the latter striking the printing ribbon and the ink moving between the arm and the impact surface when said arm is in its rear position.

Stray ink collector for impact printer

A high speed printing device having a printing head provided with printing needles. The printing device is mounted on a movable carriage which is adapted to move adjacent to a recording medium. The printing head is pneumatically operated and also is movable relative to the carriage so that the distance between the printing needles and the recording medium is variable.

High speed printer having a pneumatically actuated printing head

A protective dust cover for the needles of a mosaic printing head which eliminates the need for precision matching of segments that fit together to form holes for accepting printing needles passing therethrough. There is no precise arrangement of the parts of a dust cover to furnish an effective printing needle dust cover.

Method for making dust cover for printing needles

In a marking device for marking an information carrying medium, a marking tip is provided on an arm, and the arm is resiliently mounted by means of a leaf spring. In order to relieve stresses on the joints between the leaf spring and the arm, a region of the leaf spring to which the arm is affixed is bent, so that one portion of the leaf spring is affixed to the side of the arm toward the information carrying medium, and another portion of the leaf spring is affixed to the opposite side of the arm.

Apparatus for marking an information carrying medium

An arm in an information transmission device having a device for printing or punching holes in an information carrier. The arm is light weight, occupies less space, and operates at a higher speed than known devices of the same type. The arm is supported by a spring element and is adopted for use with an electromagnet whereby the arm is resiliently pivotable toward and away from the carrier in order to punch or print information on the carrier.

Information transmission device for point contact on an information

A direction sensing device for a punched tape which is capable of movement linearly through an optical reading apparatus. The device is of a simplified design that is easily incorporated with the optical reading apparatus. The basic structure includes means for dividing the light projected from the light source, and a pair of photosensitive members that are activated in sequence thereby determining the direction of movement of the tape.

Growing community of inventors

Lidingo, Sweden

Sven G Stenudd